Question 1

Which of the following best describes the main goal of antimicrobial chemotherapy?

Accepted Answer

To administer a drug that destroys the infective agent without harming the host’s cells

Question 2

Which of the following genera are the primary sources of antibiotics used in clinical practice?

Accepted Answer

Streptomyces and Bacillus (bacteria); Penicillium and Cephalosporium (molds)

Question 3

A physician is deciding between two antibiotics for a patient with no exceptional medical history. Drug A has a zone of inhibition of 30 mm and a therapeutic index (TI) of 1.2. Drug B has a zone of inhibition of 20 mm and a TI of 12. Which drug is the safer choice and why?

Accepted Answer

Drug B, because it has a higher therapeutic index

Question 4

Which laboratory method is more sensitive and quantitative for determining the minimum inhibitory concentration (MIC) of an antimicrobial drug?

Accepted Answer

Tube dilution test

Question 5

What does a high therapeutic index (TI) indicate about an antimicrobial drug?

Accepted Answer

It has a wide margin of safety for the patient

Question 6

Which of the following is the primary reason why drugs that target the bacterial cell wall are considered highly selectively toxic?

Accepted Answer

Human cells lack peptidoglycan

Question 7

Which of the following drugs acts by inhibiting protein synthesis at the 30S ribosomal subunit?

Accepted Answer

Streptomycin

Question 8

A patient develops a vaginal yeast infection after receiving broad-spectrum antibiotics for a urinary tract infection. This is an example of:

Accepted Answer

Superinfection

Question 9

Which of the following mechanisms of antibiotic resistance specifically inactivates penicillins and cephalosporins?

Accepted Answer

Enzymatic inactivation of the drug (e.g., beta-lactamase production)

Question 10

Which of the following best explains why antiprotozoal and antihelminthic drugs are more likely to be toxic to humans than antibacterial drugs?

Accepted Answer

Protozoa and helminths are more closely related to humans than bacteria

Question 11

Which of the following is a fluoroquinolone that inhibits DNA unwinding enzymes?

Accepted Answer

Ciprofloxacin

Question 12

Which of the following is NOT a major target of antimicrobial drugs?

Accepted Answer

Inhibition of host immune response

Question 13

Which of the following is a common adverse effect of sulfonamides?

Accepted Answer

Formation of crystals in the kidney

Question 14

Which of the following is a real-world example of how antibiotic resistance can spread in a population?

Accepted Answer

Resistant bacteria survive antibiotic treatment and transfer resistance genes to other bacteria

Question 15

Which of the following is a novel antimicrobial strategy currently under investigation?

Accepted Answer

Using RNA interference to shut down microbial gene expression

Question 16

Which of the following is a correct pairing of drug and its primary use?

Accepted Answer

Metronidazole – antiprotozoal

Question 17

Which of the following best describes a superinfection?

Accepted Answer

An infection caused by a drug-resistant microbe after normal biota are destroyed by antibiotics

Question 18

Which of the following is a major adverse effect associated with the use of polymyxin (colistin)?

Accepted Answer

Kidney damage

Question 19

Which of the following is a reason why bacteria in biofilms are often more resistant to antibiotics than free-living bacteria?

Accepted Answer

Biofilms produce a protective extracellular matrix that limits drug penetration

Question 20

Which of the following is a correct statement about the mechanism of action of sulfonamides?

Accepted Answer

They inhibit folic acid synthesis by blocking enzymes required for tetrahydrofolate production

Antimicrobial Treatment: Principles, Mechanisms, and Resistance

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